Abstract:To improve the fast response and high stability control of agile flexible spacecraft during continuous on-orbit maneuvers, a combination of observer-based adaptive control law and composite manipulation law using variable speed control moment gyroscopes (VSCMGs) as the attitude control actuators is proposed. Firstly, considering the unknown flexible modes and precise inertia during maneuvers, modal observer and rotational inertia estimators are employed to identify the unmeasurable states or parameters and the identification results are used to accurately estimate the feedforward compensation torque. The Lyapunov analysis method is utilized to prove the stability of closed-loop control system. Subsequently, based on the moment allocation capability, singularity avoidance capability, wheel speed balancing capability and final gimbal positioning capability of VSCMGs, weighted pseudo-inverse steering law and three corresponding zero motions are designed accordingly. An optimal method for the final gimbal angle is proposed based on the Jacobian matrix condition number. The deployment schemes for the zero motions in different stages of maneuvers are provided. Finally, the effectiveness of the algorithm proposed in this paper is verified by numerical simulations of continuous attitude maneuvers. The results show that the VSCMGs can switch modes smoothly during continuous maneuvers and fulfill the corresponding functions in different maneuver phases. The modal observation values and inertia estimation values converge to the true values after multiple maneuvers. The controller, after parameter identification, enables the spacecraft to reach pointing accuracy faster and more stably at the end of maneuvers.

Abstract:To mitigate the influence of strong unknown disturbances and instrument faults on observations in practical applications, and to alleviate the degradation caused by random and unmodeled interferences on the system, so as to improve the state estimation accuracy of the system in non-Gaussian noise environment and the robustness of the filter, a Gaussian-heavy-tailed switching distribution based robust Kalman filter (GHTSRKF) is proposed. Firstly, the noises are modeled as a GHTS（Gaussian-heavy-tailed switching）distribution by adaptively learning the switching probability between the Gaussian distribution and the newly designed heavy-tailed distribution. The designed GHTS distribution can model non-stationary heavy tail noise by adjusting the switching probability between the Gaussian distribution and the new heavy-tailed distribution online. The Gaussian distribution with a virtual covariance is used to deal with Gaussian noise with inaccurate covariance matrix. Secondly, two auxiliary parameters following the category distribution and the Bernoulli distribution are introduced to express the GHTS distribution as a hierarchical Gaussian form. Furthermore, the GHTSRKF is derived by utilizing the variational Bayesian method. Finally, a simulation scenario is used to compare and verify several different robust Kalman filters (RKFs). The results show that the accuracy of the proposed GHTSRKF algorithm is insensitive to the selection of initial state and exhibits higher estimation accuracy compared to other RKFs. Its root mean square errors（RMSEs）are closest to those of KF with true noise covariances（KFTNC）with accurate noise information. Compared with existing filters, GHTSRKF has better estimation performance when the system and measurement noise are unknown time-varying Gaussian noise, thus verifying the effectiveness of GHTSRKF.

Abstract:The opposing jet flow significantly alters the aerodynamic characteristics of the rocket body during the power deceleration process of the recoverable rocket. In order to obtain the influence of the opposing jet flow on the aerodynamic characteristics of the rocket body, the lift-drag coefficient of the rocket body is obtained by numerical simulation method. The change law of the lift-drag characteristic is analyzed and the representative parameters of lift-drag characteristic are propsed. Firstly, the numerical simulation of the opposing jet of blunt body was carried out, and the obtained results were compared with the published experimental data to verify the effectiveness of the numerical simulation method. Secondly, the RANS method was used to simulate various typical flight states of single-nozzle configuration rockets. The lift-drag coefficient of the rocket body changed with the angle of attack and the change law of lift-drag characteristics were obtained. The lift-drag characteristics were obtained by analyzing the flow state in the recirculation zone. Finally, the representative parameters are proposed according to the degree of influence of the opposing jet on the aerodynamic characteristics of the rocket body. Research findings indicate that the opposing jet forms a shielding effect on the rocket body and affects the lift-drag characteristics. In the presense of opposing jet, the lift-drag characteristics are greatly affected by the flight height, while the effect of flight Mach number is relatively minor, which is opposite to that observed without the opposing jet. The drag coefficient is less than 0.1 in most flight conditions, and negative drag may occur in some high-altitude flight conditions. To characterize the aerodynamic effects of the opposing jet on the rocket body, a parameter is proposed that represents the ratio of the opposing jet width to the rocket body width. This parameter effectively reflects the shielding effect of the opposing jet on the rocket body and characterizes the variations in its aerodynamic characterics of the opposing jet.

Abstract:To achieve effective detection of small faults in spacecraft attitude sensors and fault isolation of orientation sensors and inertial sensors in the presence of disturbance and measurement noise, we proposed a self-organizing recurrent neural network (SORNN) based small fault diagnosis method. Firstly, a SORNN model, including the self-organizing algorithm, termination condition, and adjustment condition, was designed to realize the adaptive adjustment of the number of hidden layer neurons and memory depth, thereby improving the fitting performance of the network. Then, a SORNN-based disturbance observer was designed for the kinematics subsystem. The network weight update algorithm was given, and the state estimation error convergence was proved. The output estimation error was passed through a low-pass filter to suppress the measurement noise of the star sensor. More rigorous residual and detection threshold were derived to improve the detection ability of small faults. Furthermore, a fault isolation observer was designed for the dynamic subsystem. The influence of unknown disturbance and noise on residual was eliminated by disturbance decoupling and disturbance observer compensation. The problem of fault isolation of different sensors was solved by using the redundancy relationship between dynamics and kinematics. Finally, the simulation results verified the effectiveness of the proposed method for detecting and isolating small faults of star sensors and gyros under the cover of disturbance and noise.

Abstract:Combat networks can accelerate the closure of the kill chain in a combat system-of-system and thus multiply combat effectiveness, but they also face the threat of focused destruction. In order to effectively and quickly recover and even improve the robustness of combat networks, the cascade failure modeling and robustness recovery methods of combat networks are studied. Firstly, to address the bias in combat network modeling, a two-layer heterogeneous group-dependent combat network model is constructed from real world. Then the conditional group-dependent failure, non-connected failure and critical overload cascading failure processes are analyzed and designed. Further, a network robustness index with operational significance is proposed. Considering the limitation of timelines and recovery resources, a prior recovery based on capacity and importance (PRCI) of boundary nodes is proposed, taking into account the attribute features of the combat network. Finally, the effectiveness and feasibility of the proposed method are validated through simulation experiments, which involve comparing and adjusting model parameters using different approaches. The results show that the recovery performance of the PRCI method is significantly better than other benchmark methods with fast onset and fewer iterations, enabling rapid and effective restoration of combat network under same conditions. Additionally, it is also found that the recovery performance of the method is proportional to the tolerance, capacity parameters, overload bearing coefficients and recovery ratio, while inversely proportional to the load parameters. These findings further provide insights for the structural optimization of combat networks.

Abstract:Rivet lap joint is a typical structure susceptible to multi-site damage, which is prone to initiate rivet holes-edge crack. It significantly threatens the safety of aircraft structures. Due to the randomness of the crack number, position, size, there exists a complex contact relationship between rivets and plates. In order to efficiently and accurately calculate the stress intensity factor of multi rivet lap joint structures for crack propagation life analysis, a weight function analysis method for rivet lap joint structure is proposed to address the complex crack issues in lap joint structures. Firstly, the crack configurations of rivet lap joint structures are reasonably simplified and classified, the corresponding weight functions are used to calculate the stress intensity factors of different crack configurations. Then, finite element analysis is conducted to compute the stress intensity factor to validate the accuracy of the weight function method. Finally, combined with the Paris crack growth formula, fatigue crack growth of the rivet lap joint structures are predicted, and the effectiveness of the present method is verified by experiments. The results show that the relative difference between the stress intensity factor calculated by the weight function method and the finite element method is less than 5%. The predicted crack growth life is in good agreement with the test results, and the computational efficiency is three orders of magnitude faster than that of the finite element method. This paper provides an effective method for the stress intensity factor and fatigue crack growth analyses of rivet lap joint structures.

Abstract:To investigate the dynamic performance and unloading failure characteristics of coal under non-hydrostatic conditions, based on 3D dynamic and static loading experiment, the effect of unloading method on the macroscopic failure characteristics of unloading coal samples after dynamic disturbance was studied. Firstly, Ф50 mm split Hopkinson pressure bar system was used to carry out the dynamic experiment of coal sample under 3D dynamic and static loading for the purpose of studying the influence of axial compression and strain rate on the dynamic response of coal samples. Secondly, based on the response surface theory, a regression model considering the interaction of factors was constructed by using the central composite test method and the significance of single factor and factor interaction were analyzed. Afterwards, combined with factor interaction, Weibull distribution and Drucker-Prager criterion, the strength statistical damage constitutive model of coal was modified. The reliability of the model was verified by comparing the theoretical and experimental results. Finally, with the help of loading and unloading electro-hydraulic servo device, the influence and mechanism of axial pressure, impact pressure and unloading mode on the failure characteristics of coal samples were explored. The results showed that the constructed strength statistical damage model has a correlation coefficient R²≥0.88, which can characterize the dynamic response behavior of coal samples. The coal samples with synchronous unloading after impact are mostly spalled, and the tensile interface moves backward and eventually disappears with the increase of axial pressure, unable to form spall failure. The failure modes of coal samples under non-synchronous unloading mainly include overall integrity, spalling and compression-shear failure. However, when the impact pressure is in the range of 0.4 to 0.6 MPa and the axial pressure is 14.5 MPa, a mixed failure mode of ‘spalling + compression-shear’ is observed.

Abstract:To solve the problem of small objects with low gravitational force and large temperature difference, we propose to use ultrasonic drill as an anchoring tool and adopt a combination of fuzzy control and constant current control strategy to achieve ultrasonic drill drilling and anchoring under low drilling pressure and high and low temperature environment conditions. The piezoelectric-driven ultrasonic drill converts high-frequency electrical energy into high-frequency mechanical vibration to drive the drilling tool to break the rock at high frequency, which has the significant advantage of very low drilling pressure and is especially suitable for drilling and anchoring operations of small bodies with weak gravity. The resonant vibration control algorithm of ultrasonic drill is studied for the drive of ultrasonic drill. Firstly, the equivalent circuit model of the ultrasonic drill transducer is established, and the impedance characteristics, load characteristics, temperature characteristics and hysteresis characteristics of the transducer are studied on the basis of the equivalent model. Secondly, the resonant frequency identification algorithm, resonant frequency tracking algorithm and constant current control algorithm are developd according to the working characteristics of ultrasonic drill. The frequency tracking algorithm based on recursive least squares estimation and the frequency tracking algorithm based on fuzzy control are studied for the resonant frequency tracking algorithm. The actual control performance of these algorithms is compared and analyzed. Finally, drilling tests are conducted under normal temperature and pressure conditions, as well as high and low temperature environments. The test results show that the designed resonant control algorithm can achieve stable driving of the ultrasonic drill under different temperature environments and different drilling object conditions. The research results show that the fuzzy control and constant current control methods proposed in this paper can effectively achieve efficient drilling under low drilling pressure and different temperatures.

Abstract:To address the issue of low comformity between traditional steady-state test conditions of hydraulic torque converters and real vehicle operating conditions, which fail to reflect the actual state of the vehicle, a cyclic operating condition for high-power tracked off-road vehicles with hydraulic torque converters is proposed. Based on real vehicle operating data from a certain type of tracked vehicle, the characteristics of torque converter in real vehicle operation are statistically analyzed. Twelve statistical feature parameters and ten ratio feature parameters are selected. The dimensionality reduction of the operating data is carried out by using principal component analysis. Clustering analysis on data segments is completed by the K-means clustering algorithm and unsupervised learning. The dynamic programming methods are used to integrate blocking conditions and typical operating condition fragments are obtained for cyclic operating condition reconstruction. The segments are smoothed by using Hanning windows. The cyclic operating conditions based on real vehicle data that align with the operational characteristics of the hydraulic torque converters during vehicle operation are constructed. The opimization is performed by simulated annealing and multi-objective particle swarm algorithm to build a cyclic condition based on the real vehicle data to fit the real vehicle operation characteristics of the torque converter, taking the average error of the main eigenvalues of the cyclic condition and the overall data, the sum of the speed difference and the slope difference at the connection as the targets. The research shows that the final condition consists of impeller speed-time and blocking signal-time. The average relative error of the main feature parameters is 2.92%, which is consistent with the performance of the real vehicle data. This research provides a new approach to design reliabile test conditions for hydraulic torque converters.

Abstract:Imitating the human visual characteristics has become a research hot and challenging research topic for machines to move towards intelligent perception and intelligent cognition. Human eyes are more sensitive to edge of objects in the scene because edge contains abundant information. To realize this visual characteristic in machines, a feature point extraction and matching method of humanoid-eye binocular images is proposed. Firstly, smallest univalue segment assimilating nucleus (SUSAN) operator with outstanding edge feature extraction capability is selected as feature detector. Then, the sampling neighborhood of scale invariant feature transform (SIFT) descriptor is improved to reduce the matching error of gradient information far away from feature points due to viewpoint and view direction differences, and the main gradient information close to feature points is retained. Whereafter, a multi-scale structure is established for the input image, and the main gradient information of the same feature is computed at different scales. Finally, the square root kernel is used to compare the similarity of the gradient information, and the multi-scale descriptor is generated to enhance the uniqueness of the description vector. In the experiment, a variety of evaluation indexes are used to evaluate the proposed multi-scale descriptor and overall algorithm respectively, and compared with the classical SIFT, speeded up robust features (SURF), Root-SIFT and the advanced boosted efficient binary local image descriptor (BEBLID), SuperGlue, DFM algorithms. The results show that the proposed multi-scale descriptor improves the matching accuracy of edge feature points and has stronger adaptability to illumination changes, thereby demonstrating better matching stability. Compared with other algorithms, the proposed algorithm has higher matching accuracy.

Abstract:To improve the reliability and service life of wet clutches in heavy-duty vehicle transmission systems, a wet clutches torque model considering interface contact state was established. The influence of different parameters on the clutch torque characteristics was studied through the model. Firstly, a simulation and modeling approach was employed to simulate the wet clutch, incorporating interface contact state parameters,and establishing a wet clutch oil charging model and a combination model. Secondly, a wet clutch torque test was conducted on the SAE#2 test bench, and the simulation results were compared with the clutch test data to verify the effectiveness of the simulation model. Finally, the influence of oil pressure, oil temperature, and disc shape on the wet clutch torque characteristics was studied using the combined model. The findings indicate that model considering interface contact states has higher accuracy compared to traditional models, with an improvement of 22.30%. As the control oil pressure decreases, the total torque of the clutch decreases. When the pressure decreases from 1.5 MPa to 1.0 MPa, the peak torque decreases by 22.38%, and the braking time extends by 46.05% simultaneously. The temperature of lubricating oil has a certain degree of influence on the viscous torque and frictional torque of the clutch. The higher the temperature, the smaller the viscous torque, the greater the frictional torque, and the overall braking time slightly decreases. The impact of friction disc shape on clutch torque is mainly reflected in the time of torque generation, and an increase in disc shape leads to an increase in clutch braking time.

Abstract:To characterize the elastic modulus and yield strength of metallic materials by Knoop hardness, the modified Marshall model and Conway model were proposed to characterize the elastic modulus, and the modified Lockett, Yu, Marsh, Johnson and Vandeperre models were proposed to characterize the yield strength, broadening the new application of Knoop hardness to the characterization of mechanical properties of metallic materials. Knoop hardness tests were carried out on 35 metals. The positive indentation size effect of Knoop hardness (hardness increases with the decrease in load) was analyzed by Meyer's law, elastic-plastic deformation (EPD) model, Hays-Kendall model, and proportional specimen resistance (PSR) model. It was found that the hardness under large loads can be approximated to be constant, and can be used to represent true hardness of the material. For the first time, the influence of pile-up around the short diagonal of Knoop indent was considered to modify Marshall model and Conway model as follows: the constant parameter α in the original Marshall model was modified as a quadratic function of b/d (the ratio of the short diagonal to the long diagonal of the residual Knoop imprint), and a correction coefficient β linearly increasing with the square of b/d was introduced to Conway model. By comparing the values of yield strength in the literature and those calculated by original models, a correction coefficient k was introduced to modify Lockett, Yu, Marsh, Johnson and Vandeperre models for the calculation of yield strength of metals for the first time. The results showed that except for Ti6Al4V and Sn, values of elastic modulus obtained from the modified models were consistent with those from instrumented indentation, with a confidence degree no less than 0.94. Similarly, except for spring steel 60Si2Mn, values of yield strength obtained from the modified models were consistent with those in the literature, with a confidence degree no less than 0.90.

Abstract:To explore the lubrication characteristics between the contact surfaces of the main bearings of RV reducer under the condition of elastohydrodynamic lubrication(EHL), a numerical model for point contact EHL of main bearings is proposed based on the non-Newtonian characteristics of grease and the fractal theory of rough surface. Firstly, the model is numerically solved to obtain the distribution of grease film pressure and grease film thickness. Then, the model is compared with the numerical results and experimental results of other point contact elastohydrodynamic lubrication models to validate the accuracy of the proposed model. Finally, the effects of rheological index, fractal dimension, entrainment velocity, load and grease viscosity on the lubrication performance of the main bearing under smooth and rough conditions are analyzed. The research shows that the more obvious the non-Newtonian property of the grease, the smaller the thickness of the grease film is and the less obvious the necking phenomenon. The pressure of the grease film near the contact area is more consistent with the Hertz pressure distribution, and the secondary pressure peak gradually disappears. Considering the elastohydrodynamic lubrication characteristics of the fractal rough surface of the main bearing is more realistic. Increasing the fractal dimension increases the real contact area of the contact area, which is beneficial to reduce the pressure of the grease film and increase the thickness of the grease film. The entrainment velocity, load and grease viscosity have significant impact on the thickness distribution of the grease film, while their influence on the pressure distribution of the grease film is comparatively smaller. Larger grease film thickness and the minimum film thickness contribute to the resistance of grease film breakdown and promote het formation of hydrodynamic lubrication.

Abstract:To explore the feasibility of using a support design of lighting environment in subway dispatching centers to alleviate the mental fatigue of dispatchers and thus achieve human-machine efficiency enhancement, the effects and mechanism of dynamic lighting on fatigued subway dispatchers were investigated. We built a visible spectrum artificial lighting experimental platform based on the laboratory environment and modulated two lighting parameters (conventional lighting: 4 000 K, 500 lx; dynamic lighting: 4 000-12 000 K, 500 lx). On this basis, an ergonomics experiment was carried out with a single-blind within-subject design. Based on subway scheduling task analysis, PVT, N-back, and MATB-Ⅱ tasks were designed to characterize continuous attention, working memory, and executive control functions respectively. Sixteen participants’ neurobehavioral responses including subjective assessment, behavioral performance, and EEG (electroencephalogram) indicators during different ambient light were collected, compared and analyzed. The results showed that, compared with conventional lighting, fatigued participants feel more alert and have a more posive mood. Furthermore, their continuous attention, working memory, and executive control were significantly improved under dynamic lighting. The results of EEG data revealed that the fatigue intervention mechanism of dynamic lighting may be due to the effective inhibition of α, θ, and α-θ activities in the frontal lobe. The current results have preliminarily discovered the effects of dynamic lighting on mental fatigue, thus providing the basis for the lighting design and fatigue management of urban rail transit.

Abstract:Due to its self-lubricity and self-sealing, ferrofluid micropump is more in line with the needs of microfluidic technology applied in biomedicine, life science, chemical analysis, aerospace and other fields. However, current structural designs face challenges in simultaneously achieving simple processing, high reliability, stable flow characteristics, so the application and development are limited. In order to improve the reliability and stability of ferrofluid micropump and promote its development and application, a new type of centrifugal ferrofluid micropump is designed based on the external field control principle of ferrofluid, the magnetorheological effect and the hydrodynamic behavior between medium fluid. Numerical calculations are employed to analyze the flow characteristics of medium fluid. The results show that the micropump can effectively realize the pumping process.At a rotating speed of 10 r/min, the pumping flow can reach 0.07 kg/T in one cycle, and the medium fluid mass exchange between the inlet and outlet of the pump chamber can be blocked under the alternating action of two ferrofluid. Due to the dynamic and static interaction between ferrofluid and the pump chamber structure, the outlet flow rate has a slight pulsation (On the order of 10^-5), but it still remains in laminar flow state (Re＜1). Moreover, due to mechanical factors such as inertia force being related to characteristic size while viscous force and characteristic size are unrelated, the pumping power of the structure is highly sensitive to outlet size and length. As a result, effective pumping cannot be achieved at a speed of 4 r/min and the length of the outlet section is 9 mm. The pressure fluctuation and the self-sealing performance of the phase interface between the ferrofluid and the pumping medium fluid are analyzed simultaneously. The peak value of the pressure fluctuation on the phase interface is much smaller than the self-sealing performance of the ferrofluid, differing by three orders of magnitude. The feasibility of the centrifugal ferrofluid driver is verified from the perspective of the sealing stability and the interface stability of the ferrofluid.

Abstract:To improve the heating effect of hot air heating on asphalt pavement during hot in-place recycling (HIR), the hot-air impinging jet convective heat transfer and the heat conduction were regarded as conjugate heat-transfer process, and a theoretical model of conjugate heat-transfer for impinging jet for hot air heating asphalt pavement was established. Based on the finite volume method, the general discrete equation of conjugate heat-transfer model was presented. The temperature field distribution in the whole solution domain was obtained by using the pressure/velocity coupled semi-implicit algorithm (SIMPLE). The average heat flux and average heat-transfer coefficient were selected to reflect the heating effect on the asphalt pavement. The influence degree of hot-air outlet velocity and hot-air outlet temperature on heating effect was studied by orthogonal experiments. The simulation and experimental results show that there is a high degree of agreement between the theoretical calculation and the experiment temperature distribution, with an average error of 8.4%. Both average heat flux and average heat-transfer coefficient decrease sharply from the maximum value at the beginning of heating, and then gradually decrease to equilibrium. The simulation and the experiment of both average heat flux and average heat-transfer coefficient have the same trend, and the average errors are 6.4% and 7.8%, respectively. Both the velocity and the temperature of hot-air outlet have a significant effect on the average heat flux, while the hot-air outlet velocity has a significant effect on the average heat-transfer coefficient. However, the influence of hot-air outlet temperature on the average heat-transfer coefficient is relatively insignificant compared to the average heat flux. The research results provide a theoretical basis for temperature control and the design of hot-air heating equipment during HIR.

Abstract:To satisfy the needs of plant cultivation in space, the scenario of a space plant cultivation facility(SPCF) was conducted, based on the limited resources and microgravity in space environments. The study contents included water and nutrient control around roots, atmospheric environment control in cultivation room, and light environment control, etc. The facility was designed with six functional modules, consisting of water and nutrient supply module, atmospheric environmental control module, light module, measurement and control module, cultivation room module, and root tray module. The integration and testing of the facility were carried out and the rationality of the design of each functional module was verified. Finally, the combination testing platform was used to verify the integrated performances of various functional modules of the facility, evaluate plant functions (biological characteristics, material and energy exchange, nutritional quality, and biosafety), and verify plants cultivation processes (process rationality, resource requirements and supply, and mutual impact with the environment). The verification results indicated that the performance of water supply, nutrient supply, atmospheric environmental control, illumination control, as well as the measurement and control is well, meeting the demands of plant growth in space. Lettuce grow vigorously with a production efficiency of 101.31 g (fresh weight)·(kWh)^-1·d^-1·m^-2 and a light energy utilization rate of 0.31 g (dry weight)·mol^-1 photons. More importantly, the lettuce is nutrient rich and safe for consumption. The scenario of facility design and cultivation procedures are reasonable and feasible with good performance and high production capacity. This study establishes technical foundations for the future development of plant cultivation facility targeting space environments.

Abstract:In the environmental control and life support system (ECLSS) of the extravehicular spacesuit, the removal of the moisture from the medium gas can be achieved by the dehumidifier which may effectively improve the sensitivity of the CO₂ pressure sensor. In order to adapt the usage mode and egress time of the extravehicular spacesuit, and to extend the usage times of the dehumidifier, a method of the residual oxygen purging is proposed, by which the color-changing silica gel is regenerated after dehumidification. This method aims to study the dehumidification performance, the regenerative performance and the influence of the usage mode on the dehumidification performance. Firstly, the physical properties and the dehumidification performances of the desiccants such as the calcium chloride (CaCl₂), color-changing silica gel, and fine porous silica gel are compared and analyzed using the dehumidifier. Secondly, the method of the residual oxygen purging is tested, by which the color-changing silica gel is regenerated after dehumidification. Finally, the influence of the usage mode on the dehumidification performance of the dehumidifier was experimentally investigated and compared. The experimental results indicate that the dehumidification performance of CaCl₂ is better than that of color-changing silica gel, but the CaCl₂ particle tends to collapse and short circuit after hygroscopic. Under the same condition, the continuous dehumidification time of the color-changing silica gel is 32 h, while the time of the fine porous silica gel is 23 h. After a pause of dehumidification, the dehumidification performance of the dehumidifier change. The outlet humidity of the intermittent usage mode increases with the increase in dehumidification time, which is higher than that of the normal usage mode. Furthermore, the physical characteristics of color-changing silica gel are stable, and it has a longer dehumidifying time under the conditions of the dehumidification requirements, making it more suitable for the dehumidifier in this system. Additionally, the color-changing silica gel can be recycled and has the ability to multiple dehumidify after being purged with pure oxygen. However, the discontinuous mode can lead to the redistribution of the moisture within the silica gel, reducing the overall moisture absorption capacity of the dehumidifier. This research provides fundamental data and theoretical guidance for the desiccation selection of the dehumidifier and optimization of regeneration characteristics of the extravehicular spacesuit in environmental control and life support system.